This invention relates generally to image correlators and more particularly to a magnetic resistance image correlation device.
The property of magnetic resistance (referred to hereinafter as magnetoresistance) has been known for a great number of years. It relates to the fact that the electrical resistance of certain materials is greater in a direction transverse to a magnetic field to which the material is exposed than it is in a direction parallel to the magnetic field. When a magnetoresistive material is exposed to a magnetic field, it offers the least amount of electrical resistance along a path which is parallel to the magnetic field and offers increasingly greater resistance as that path is rotated away from the direction of the magnetic field. To that end, the greatest amount of electrical resistance through the material is along a path perpendicular to the direction of the magnetic field.
Correlation devices have a wide variety of present usages and an even greater number of potential future ones. Electronic correlation devices provide an electronic means for determining whether an electronically perceived external object matches (looks the same as) a given known object. To that end, electronic correlation devices also provide a means for providing input data to a computer or for generating a signal for actuating some other electronic or electromechical system in response to the occurrence or non-occurrence of the selected object.
A few examples of systems which either use or could use correlation devices include radar detection systems for spotting enemy aircraft, missiles, etc., character recognition systems which interface with a computer, transportation systems for preventing collisions between a vehicle and another vehicle, a particular object or a person, surveillance systems and verification systems.
With regard to all of the abovementioned usages, a most important feature of the correlation device is that the device be able to scan a visual field to determine whether the object being looked for is present even when the object is not situated to be at a predetermined location within the visual field.